OBJECTIVES: I. Determine the rate of clinical benefit, in terms of the incidence of objective partial and complete response, stable disease, or minor response of more than 3 months duration, in patients with previously treated, unresectable advanced or metastatic soft tissue sarcoma treated with ecteinascidin 743. II. Determine the progression-free survival, overall survival, and response duration in patients treated with this drug. III. Determine the toxicity profile of this drug in these patients. IV. Determine the pharmacokinetic-pharmacodynamic relationship of this drug in these patients.